Recognizing familiar voices and familiar phrases is a common occurence, yet the hemispheric specialization for these processes is not yet known. This research aims to study hemispheric specialization for voices and familiar phrases (idioms and cliches) and investigate cognitive processes underlying right and/or left hemisphere abilities for these stimuli. To accomplish these goals, stimuli will be developed for testing brain-damaged patients, split-brain subjects, and normal subjects. Results from these three populations on several tests will be compared. Thorough neurological data on clinical patients will be examined in relation to their performance on the tests. To investigate voice recognition, materials on familiar and unfamiliar faces and voices, as well as environmental sounds and musical stimuli, will be prepared. Cognitive processing will be investigated by acoustically altering the voice stimuli (to test whether the right hemisphere is superior at identifying a degraded stimulus in the auditory modality, as has been shown for the visual modality). In addition, a dichotic listening task will engage left or right hemisphere for the same stimuli (subjects will identify words in one condition, voices in another). To investigate familiar phrase recognition, test materials will consiste of familiar, novel, and nonsense phrases presented to the three populations, with altered stimuli presented also dichotically to normal subjects. Our hypothesis is that the right hemisphere is specialized for recognizing voices and familiar phrases. These studies have implications for rehabilitation of brain-damaged individuals, in that voice recognition may be impaired in certain instances of brain damage (as is face recognition). In addition, if the right hemisphere can deal with familiar phrases, then this ability can be drawn upon by speech therapists in treatments of aphasic patients.